The START trial was designed to address the question: In HIV-1 (subsequently referred to as HIV) infected asymptomatic participants with a CD4+ count greater than 500 cells/mm3, is immediate use of antiretroviral therapy (ART) superior to deferral of ART until the CD4+ count declines to 350 cells/mm3 or AIDS develops in terms of morbidity and mortality? The study is being conducted at 237 sites in 35 countries. Global enrolment closed with 4,688 participants enrolled.